DMA 73

Introduction

Thank you for choosing the Rackmount DMA 73. Heritage Audio is dedicated to bringing you 'the sound of yesterday for tomorrow'. We specialize in capturing that unique, enticing sound that everybody has fallen in love with. For years engineers, producers and musicians have been yearning for that classic vibe. Usually the only option is to search for old, used original equipment that is almost always in a questionable state of operation. This brings with it a whole lot of other issues, making the experience less than desirable. Not to mention the very high prices asked for this equipment, which makes them virtually unobtainable for the great majority. Now it's possible to obtain that same sound with a brand new piece that will give you all the problem-free, heavy-duty use you'll need for years of music making history.

Peter Rodriguez
CEO
Heritage Audio - Madrid, Spain

© 2022 Heritage Audio S.L. is the sole owner of the copyright of all information and drawings contained in this manual which are not to be copied or reproduced by any means or disclosed in part or whole to any third party without written permission. Heritage Audio reserves the right to alter specifications without notice. The information in this manual has been carefully checked and is believed to be accurate at the time of publication. However, no responsibility is taken by us for inaccuracies, errors or omissions nor any liability assumed for any loss or damage resulting either directly or indirectly from use of the information contained within it.

Description

73-style Mic Preamp

The DMA 73 is Heritage Audio's top-of-the-line stereo microphone preamplifier, offering unparalleled authenticity, quality of construction, and sound. It is a true dual 3-stage 73-style mic preamp in a 1 rack unit format, incorporating accurate vintage features tailored for modern producers, engineers, and musicians. The DMA 73 utilizes discrete circuitry and conventional, vintage-style components, delivering a faithful 3-stage all Class A 73 preamp. Custom styroflex and tantalum capacitors are used throughout, with no compromises in quality. Each unit is completely hand-made and hand-wired in Heritage Audio's Madrid, Spain facility, employing traditional through-hole circuitry reminiscent of the 1970s, requiring significant skilled labor for production. The results are described as stunning.

Carnhill input transformers are exclusively hand-wound at the Oxford factory for Heritage Audio, housed in vintage-correct green metal cases for meticulous detail. This vintage character is guaranteed and unique to Heritage Audio products. The line mode allows for reamping prerecorded tracks, adding vintage Class A mojo to recordings, and utilizes the mic input transformer. The DI circuit is an all discrete Class A JFET circuit positioned before the microphone transformer, ensuring its unique character is preserved. Since its introduction in 2012, Heritage Audio's DI circuit has become a classic for direct bass guitar recording.

When seeking the ultimate vintage 73 preamp experience, it's important to remember: Transformers can make all the difference in the world.

The DMA 73 Transformers:

The DMA 73 features correct transformers, a critical component for any 73-style preamp. Heritage Audio has gone beyond the competition by using a Carnhill gapped output transformer, the same used across Heritage Audio's product line, made exclusively in the St Ives factory. The input transformer is also exclusive, made in Carnhill's Oxford factory, significantly contributing to the unit's sonic character and 'mojo'. It is the same transformer found in Heritage Audio's higher-end 80 Series modules, accounting for sonic differences between the DMA 73 and its competitors. For an exclusive sound, do not settle for non-exclusive transformers.

Getting Started

Front Panel

Rear Panel

Applications

Microphone Application

Connect condenser microphones (Left and Right channels) to the respective MIC INPUTs on the rear panel. Activate the +48 V Phantom Power switch on the front panel if required for the microphones. The output signal from the DMA 73 can then be routed via the LINE OUTPUTs to an audio interface or USB computer for recording.

D.I. Application

Connect instruments such as guitars or basses directly to the D.I. INPUTs on the front panel. An optional guitar FX pedal can be placed between the instrument and the D.I. input. The processed signal can be routed via the LINE OUTPUTs to an audio interface or USB computer.

Line Application

Connect line-level sources, such as keyboards or other audio equipment, to the LINE INPUTs on the rear panel. Ensure the LINE switch on the front panel is activated to select the line input source. The output signal can then be routed via the LINE OUTPUTs to an audio interface or USB computer.

Specifications

• Microphone input impedance: High = 1200 Ω minimum; Low = 300 Ω minimum. Higher gain positions gradually have greater impedances, optimum for low gain ribbon mics. Input is transformer balanced and floating.
• Line input impedance: 10 kΩ bridging, transformer balanced and floating.
• Output impedance: Less than 75 Ω, Carnhill transformer balanced and floating, to drive a load of 600 Ω (Factory terminated).
• D.I. input impedance: Greater than 2 MΩ, unbalanced.
• Maximum output: Greater than +26 dBu into 600 Ω (internally terminated).
• THD: Less than 0.025% at 1 kHz, Less than 0.05% at 100 Hz.
• Frequency response: 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB).
• Maximum Gain: Slightly greater than 80 dB.
• Output stage noise: Less than -100 dBu.
• Power consumption: 88 mA per rail @ ±16 V DC. (External linear PSU recommended to avoid electromagnetic radiation into the audio transformers, a.k.a. hum).
• Dimensions DMA 73 (W x H x L): 482 mm x 44 mm (1 Rack unit) x 184 mm.
• Weight: 3.4 Kg.
• Dimensions External PSU (W x H x L): 200 mm x 44 mm (1 Rack unit) x 160 mm.
• Weight: 1.9 Kg.

Signal Flow

The signal path for each channel (Left and Right) is as follows: The input signal enters via the MIC/LINE INPUT or D.I. input. It then passes through a PAD (if engaged), a LOZ impedance selector, and the INPUT AMP. A HIGH PASS FILTER is applied before reaching the OUTPUT AMP. Finally, the signal exits through the LINE OUTPUT, with PHASE adjustment available. Carnhill transformers are integral components at various stages of the signal path.

Trouble Shooting

For any further doubts or questions please get in contact with us at: support@heritageaudio.com

Warranty Statement

Limited 2 Year Warranty

Heritage Audio DMA 73 is warranted by Heritage Audio SL to be free from defects in materials and workmanship for the period of 2 years to the original purchaser. In the event of such defects, the product will be repaired without charge or, at Heritage Audio's option, replaced with a new one if delivered to Heritage Audio prepaid, together with a copy of the sales slip or other proof of purchase date. The warranty excludes problems due to normal wear, abuse, shipping damage, or failure to use the product in accordance with the specifications.

Heritage Audio shall not be liable for damages based upon inconvenience, loss of use of the product, loss of time, interrupted operation, or commercial loss or any other damages, whether incidental, consequential, or otherwise.

This warranty is not transferable.

Heritage Audio and the Heritage Audio “H” logos are registered Trademarks owned and/or licensed by Heritage Audio.

Registration

Please visit our website: https://heritageaudio.com/registration/

Recall Sheets

Forms are provided for recording session details, track, instrument, connected equipment, notes, and switch settings (ON/OFF) for each channel. These sheets help in recalling specific settings for future sessions.